Equalizing device for steam-pumps.



Patented Sept. 9, 902.

4 Sheets-Sheet- P. F. ODDIE. EGUALIZING DEVICE FOR STEAM PUMPS.

(Application filgd Oct. 24', 1901.)

(No Model.)

cams PETERS ca, WASHINGTON u Patented Sept-9, I902.

P. F. ODDIE. EOUALIZING DEVICE FOR STEAM PUMPS.

(Application filed Oct. 24, 1901.)

4 Sheets-Sheet 3.

(No Model.)

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No. 708,9!2. Phtented Sept. 9, I902." P.'F. onms.

EOUALIZING DEVICE FOR STEAM PUMPS.

(Application filed Oct. 24, 1901.) w (No Model.) 4 Sheets-Sheet 4.

' UNITED STATES PATENT OFFICE.

PHILIP FRANCIS ODDIE, OF OSCHERSLEBEN, GERMANY.

EQUALIZING DEVICE FOR STEAM-PUMPS.

SPECIFICATION forming part of Letters Patent No. 708,912, datedSeptember 9, 1902. Application filed October 24, 1901. Serial No.79,868. (No model.)

To all whom it may concern.-

Be it known that I, PHILIP FRANCIS ODDIE, civil engineer, a subject ofthe King of Great Britain and Ireland, residing at Oschersleben, nearMagdeburg, Germany, have invented new and useful Improvements inCompensating or Equalizing Devices for Direct-Acting Steam -Pumps, ofwhich the following is a specification.

My invention relates to a compensating or equalizing device fordirect-acting steampumps. I

The value of myinvention lies in the method employed for increasing theeffective power of the compensator in the middle of the stroke.

The invention is illustrated in the annexed drawings, in which Figure 1represents the arrangement of the rods or links operated by. thecross-head, whereby the excess of power of the pump-piston istransmitted to an equalizing-piston, and the arrangement of the valvecontrolled by the compensating'piston. Fig. 2 is a modifiedarrangementof the valve. Fig. 3 shows the valve'arranged within the hollowcompensating piston. Fig. 4 is a modified form of my invention. Fig. 5is another modified form.

The improved arrangement aifords a very good equalization of pressure,the pressure means behind the piston being either water or air undervariable pressure, or air and water or other liquid can be employedsimultaneously. The pressing medium acting upon the equalizing-pistoncan, according to the present invention, by means of convenient valves,be closed at certain times, whereby the piston is prevented from actingupon the pump piston at inconvenient times.

a is the compensating cylinder, and b the compensating piston orplunger. 0 and d are links or levers pivoted together at e. The lowerend of the lower lever c is guided by a lateral rodfand rests freelyuponthe equalizing-piston 6 without being connected thereto. The two leversc and d are pivoted together by means of a bolt 6, upon which isrotatably mounted a roller g, which can slide in a slot h in thecross-head k of the pumppiston rod 2'. The cross-head 7c is connectedwith the steam-piston and pump-piston rods Z and t, which are guided inconvenient bearings m, mounted upon the engine -frame. The space beneaththe equalizing-plunger b is connected through a conduit 17. with an airchamber or vessel 0. The latter is partly filled with oil or otherliquid. The remaining space is filled with compressed air, which ismaintained under constant pressure. In Fig. 1 I have not shown any meansfor accomplishing this end. It is obvious, however, that this may beaccomplished in numerous ways. For instance, a suitable compressed airreservoir, as shown at 5 Fig. 4:, could be connected by a branch pipe tothe top" of the reservoir 0, a suitable valve 0 being arranged in thebranch pipe to control the delivery therethrough, as shown in Fig. 3.The power acting in the first half of the stroke upon theequalizing-plunger is given back to the engine during the second half ofthe stroke, when the pressure acting upon the steam-piston is reduced inconsequence of the expansion of the working fluid.

In orderto regulate the length of the stroke of the steam and waterpistons and to prevent the compensating plunger from driving thepump-pistons against the cylinder-covers, a valve p is arranged in theconduit n, which connects the air vessel 0 with the interior of thecompensating cylinder a, said valve being positively closed before thepistons finish their stroke. The pressure acting below the plunger iscut oif by closing thevalve, and consequently the piston is put out ofaction. The valve can be controlled in various manners. It can, forinstance, be operated by means of a pivoted lever q, one end of whichconstantly bears against the inner face of the plunger, while its otherand shorter end engages a projection on the valve-spindle, provided witha valve-closing spring 7.

According to the modified arrangement in Fig. 2 the valve is constructedas a piston valve and is controlled by an arm .9, secured to the upperside of the plunger; The valvespindle passes freely through this arm andis constantly pressed downward by a spring 15, so as to maintain thevalve in its open position. If, however, the plunger has reached thepermissible limit of its outer stroke, the arm on the plunger comes incontact with a nut or projection u on the valve-spindle. On

the further ascent of the plunger the pistonvalve is raised and closesthe connection between the cylinder and the compressor and -reservoir,thus preventing the pressure mehowever, with lateral slots 1; nearthereto.

The plunger is hollow and provided in its inner end with a sleeve to,which fits tightly upon the pipe. Consequently the fluid passes from thepipe through the slots and into the pistons and cylinder. \Vhen,however, the plunger moves outward toward the end of its stroke, thesleeve passes over the slots and closes the latter, thereby preventingthe driving medium from further entering the compensating cylinder.

According to a modified construction the operation is effected by thecross-head in such a way that while the latter reciprocates in astraight line the driven end of the lower lever connected to thecross-head can move in an are described from its fulcrum or pivotalpoint arranged in the axial line of the equalizing-cylinder. The upperlever is extended beyond its pivotal point, and to its extensionislinked a rod which is used as an operating means for the valve-gear ofthe steam-cylinder s. To insure safety, usually double levers arearranged, in which case if distribution and expansion valves or slidesare used the extensionotthe second lever serves for operating theexpansion-slides. It has been practically proved that the ratio ofmotion of the links is very favorable for the operation of thevalve-gear. The equalizing-cylinder can of course be arranged eitherabove or below the cross-head of the steam cylinder and pumps, orat theside if the latter are arranged vertically. 1

Fig. 4 shows a simple and convenient method of producing a perfectequalization. The compensating cylinder, piston, rods, crosshead, andleverage are the same as shown in Fig. 1. The chamber a is filled withoil, water, or other liquid to a certain height, while the plunger ofthe compensator is hollow and forms in its upper portion an air vessel.The end of a pipe I), to which is attached the small valve Z), passesinto the air-space of the compensating plunger. The other end of thepipe is in communication with an airreservoir Z2 which is kept at therequired constant pressure by means of a small air-compressor or by someother convenient source. At the middle of the stroke the compensatingplunger is in its lowest position and is made to open this valve.Consequently air is admitted to the air vessel in the plunger at thepressure of the reservoir. As the stroke proceeds the plunger rises, thevalve is closed, and the air inclosed in the hollow plunger expands anddecreases in pressure until the end of the strokeis reached. On thereturn stroke the reverse action takes place. The air is compressed andincreases in pressure as the plunger descends until the middle of thestroke is again reached, when the valve is again opened andcommunication made with the air-reservoir. Thus the pressure in themiddle of the stroke is always maintained the same as that in thereservoir. The liquid in the chamber a serves two objects-first, byaltering the level of the liquid the size of the air-chamber orclearance-space can be reduced or enlarged at will, and consequently theditferenceof pressure between the middle and the ends of the strokeexactly regulated to suitany given steam-pressure and ratios ofexpansion in the main steam-cylinders; secondly, the liquid forms a sealaround the plunger, and thus prevents air-leakage through thestuffing-box gland.

I can of course without departing from the principle of the inventionalso arrange that the pressure at the extreme ends shall be the pressureof the reservoir. It is then only necessary to supply in place of thevalve 5 an automatic valve, which shall open and supply air whenever thepressure in the plunger shall have fallen slightly below that of thereservoir. Fig. 5. In this case the air at the end of the stroke ispractically the same as the pressure in the reservoir; but as the strokeproceeds the air in the compensating plunger descends until the middleof the stroke is reached, when the pressure is at its maximum. Afterthis the plunger begins to ascend, the air expanding and falling inpressure to the end of the stroke. The amount of this compression Suchan arrangement is shown in is regulated, as before, by the height of theoil in the chamber a.

Having now particularly described and ascertained the nature of the saidinvention and in what manner the same is to be performed, I declare thatwhat I claim is- 1. In a compensator for direct-acting engines, thecombination with the main pistonrod provided with a cross-head, linkspivoted together in said cross-head, and one of said links being alsopivoted to a guide-rod, of a piston working in a compensating cylinderfor transmitting to the main piston-rod in the second half of thestroke, through the medium of said links, the power stored up in thefirst half of the stroke, and means for arresting the action of saidcompensating piston at predetermined poi nts,substantially as described.

2. In a compensator for direct-acting engines, the combination with themain pistonrod provided with a cross-head, links pivoted together insaid cross-head, and one of said links being also pivoted to aguide-rod, of a piston working in a compensating cylinder fortransmitting to the main piston-rod inthe second half of the stroke,through the medium of said links, the power stored up in the first halfof the stroke, and means operated by said compensating piston forrelieving the pressure thereon at predetermined times,substantially asdescribed.

3. In a compensator for direct-acting engines, the combination with amain piston rod, provided with a cross-head, links pivoted together insaid cross-head, and one of said links being also pivoted to aguide-rod, of a piston Working in the compensating cylinder fortransmitting to the main piston-rod in the second half of the stroke,through the medium of said links, the power stored up in the first halfof the stroke, a compressor-flask in communication with saidcompensator-cylinder, and a valve between said flask and cylinder, andmeans operated by said compensating piston for controlling the admissionof pressure to said compensating cylinder, substantially as described.

4. In a compensator for direct-acting engines, the combination with themain pistonrod provided with a cross-head, links pivoted together insaid cross-head, and one of said links being also pivoted to aguide-rod, of a piston working in the compensating cylinder fortransmitting to the main piston-rod in the second half of the stroke,through the medium of said links, the power stored up in the first halfof the stroke, a compressor-fiaskin communication with saidcompensator-cylinder, means for maintaining a constant pressure in saidflask, a valve between said flask and cylinder, and. means operated bysaid compensating piston for controlling the admission of pressure tosaid compensating cylinder, substantially as described.

5. In a compensator for direct-acting engines, the combination with themain pistonrod, acompensating cylinder, a piston in said cylinder, andmeans for transmitting motion from said second piston to the first, of acompressor-flask, a valve between said flask and cylinder, a leverhaving one arm engaging said valve and another arm operated by saidsecond piston for controlling the admission of pressure to saidcylinder, substantially as described.

6. In a compensator for direct-acting engines, the combination with themain pistonrod, a compensating cylinder, a piston in said cylinder, andmeans for transmitting motion from said second piston to the first, of acompressor-flask, a valve between said flask and cylinder, and an arm onsaid piston engaging a stop on the valve-stem for controlling the actionof said valve, substantially as described. v

7. In a compensator for direct-acting engines, the combination with themain pistonrod, a compensating cylinder, a hollow piston in saidcylinder, and means for transmitting motion from said second piston tothe first; of a compressor flask or reservoir, a pipe or conduitprovided with apertures on the sides thereof, extending from saidreservoir into said hollow piston, and a sleeve on said piston adaptedto close said apertures, substantially as described.

8. In a compressor for direct-acting engines,

the combination with the main piston-rod, a compensating cylinder, ahollow piston in said cylinder, and means for transmitting motion fromsaid second piston to the first; ofa compressor flask or reservoir, apipe or conduit extending from said reservoir into said hollow piston,and a valve on the end of said pipe adapted to be operated by saidpiston, substantially as described.

9. In a compensator for direct-acting engines, the combination with themain pistonrod, a compensating cylinder, a hollow piston in saidcylinder, and means for transmitting motion from said second piston tothe first, of a compressor flask or reservoir, a pipe or conduitextending from said reservoir into said hollow piston, and a valve onsaid pipe operated when the pressure in said compensating cylinder fallsbelow that in the reservoir, substantially as described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

PHILIP FRANCIS ODDIE.

Witnesses:

L. PALMER, I HERMANN HOPPE.

